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Poinsettia: Lower Leaf Blotches

Wed, Oct 6th, 2021, created by Brian Whipker

We are midway into the poinsettia season. This is the time of year that lower leaf blotches can appear on poinsettias.  The more advanced symptoms are olive-green circular spots that can be noticed on both green and later yellowing leaves.

These symptoms are of a phosphorus (P) deficiency.  While low P rates help to avoid excessive plant stretch and avoid wasteful applications, too low of a rate can negatively impact plant health.  In general 15 to 20ppm P will be ample to sustain plant growth and avoid excessive stem elongation.

For additional details, view e-GRO Alert 3-54 or click on the link contained in the Alert to watch the video.

http://e-gro.org/pdf/354b.pdf




About the Author:

Brian Whipker

Professor, Horticulture, North Carolina State University

Brian E. Whipker is a professor of floriculture at North Carolina State University. He has an appointment split between extension and research, but also teaches the graduate level plant nutrition course at NC State. His specialization is plant nutrition, plant growth regulators, and problem diagnostics. He brings over 30 year of experience in diagnosing grower plant problems.

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